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Unlike shield volcanoes, they are characterized by a steep profile and periodic, often alternating, explosive eruptions and effusive eruptions. Some have collapsed craters called calderas . The central core of a stratocone is commonly dominated by a central core of intrusive rocks that range from around 500 meters (1,600 ft) to over several ...
The most active shield volcano in Africa is Nyamuragira. Eruptions at the shield volcano are generally centered within the large summit caldera or on the numerous fissures and cinder cones on the volcano's flanks. Lava flows from the most recent century extend down the flanks more than 30 km (19 mi) from the summit, reaching as far as Lake Kivu.
Mount Edziza, a large shield volcano in northwestern British Columbia. The most active volcanic region of the northern Pacific Northwest is called the Northern Cordilleran Volcanic Province (sometimes called the Stikine Volcanic Belt). It contains more than 100 young volcanoes and several eruptions known to have occurred within the last 400 years.
A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers of hardened lava and tephra. [1] Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and explosive eruptions. [2] Some have collapsed summit craters called calderas. [3]
The Waw an Namus volcano is surrounded by an apron of dark tephra, which has a notable color contrast to the surrounding Sahara Desert. Africa's volcanoes have had an impact on the fossil record. Geographically a part of Africa, El Hierro is a shield volcano and the youngest and smallest of the Canary Islands.
Cinder cones are also commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. [3] For example, geologists have identified nearly 100 cinder cones on the flanks of Mauna Kea, a shield volcano located on the island of Hawaii. [3] Such cinder cones likely represent the final stages of activity of a mafic volcano. [11]
Then, from 4.9 to 3.9 Ma, a third shield volcano (Anaga shield volcano) was active in the northeastern part of Tenerife; the remains of this volcano are the Anaga massif. [90] The lavas of these three shield volcanoes gradually formed a combined volcanic edifice that accounts for 90% of Tenerife's current volume. [91]
[8] [9] It is about 65 kilometres (40 miles) long and 20 kilometres (12 miles) wide, consisting of several stratovolcanoes, shield volcanoes, subglacial volcanoes, lava domes and cinder cones. [10] [11] [12] This volcanic complex includes a broad, steep-sided, intermontane plateau that rises from a base elevation of 760 or 816 metres (2,500 or ...